Food habit and climate change impacts on agricultural water security during the peak population period in China

Rapid changes in food habits, climate, and population size are expected to substantially challenge the sustainable use of China's agricultural water supply, undoubtedly increasing the uncertainty of China's food security. This study analyzes the change characteristics of China's food habits during 1981-2017, and the amount agricultural water for food production during peak population period (2029-2033) has also projected based on different food habits and climate scenarios. The results show that China's food habits changed dramatically from mainly vegetable-dominated to animal-dominated during 1981-2017. Compared to the historical period (2013-2017), the decrease in precipitation and the increase in evapotranspiration in the peak population period will increase the drought degree in China's thirteen main food producing provinces. During peak population period, the irrigation water demand will increase to 298.0-314.7 billion m(3) under current food habits and 319.4-337.8 billion m(3) under recommended food habits in different climate scenarios, respectively; these values are much higher than those of the historical period (e.g., 195.7 billion m(3) in 2017). Moreover, compared with 2017, China's future per capita irrigation water demand is expected to increase by 63.3-74.8 m(3) due to climate change; if food habit changes are further adopted, then per capita irrigation water demand is expected to increase even more, by 77.9-90.5 m(3). This study also proposes various measures to ensure China's agricultural water security based on the presented findings.